1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/sparc/kernel/traps.c
4 *
5 * Copyright 1995, 2008 David S. Miller (davem@davemloft.net)
6 * Copyright 2000 Jakub Jelinek (jakub@redhat.com)
7 */
8
9/*
10 * I hate traps on the sparc, grrr...
11 */
12
13#include <linux/cpu.h>
14#include <linux/sched/mm.h>
15#include <linux/sched/debug.h>
16#include <linux/mm_types.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/smp.h>
20#include <linux/kdebug.h>
21#include <linux/export.h>
22#include <linux/pgtable.h>
23
24#include <asm/delay.h>
25#include <asm/ptrace.h>
26#include <asm/oplib.h>
27#include <asm/page.h>
28#include <asm/unistd.h>
29#include <asm/traps.h>
30
31#include "entry.h"
32#include "kernel.h"
33
34/* #define TRAP_DEBUG */
35
36static void instruction_dump(unsigned long *pc)
37{
38	int i;
39
40	if((((unsigned long) pc) & 3))
41                return;
42
43	for(i = -3; i < 6; i++)
44		printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
45	printk("\n");
46}
47
48#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
49#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
50
51void __noreturn die_if_kernel(char *str, struct pt_regs *regs)
52{
53	static int die_counter;
54	int count = 0;
55
56	/* Amuse the user. */
57	printk(
58"              \\|/ ____ \\|/\n"
59"              \"@'/ ,. \\`@\"\n"
60"              /_| \\__/ |_\\\n"
61"                 \\__U_/\n");
62
63	printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
64	show_regs(regs);
65	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
66
67	__SAVE; __SAVE; __SAVE; __SAVE;
68	__SAVE; __SAVE; __SAVE; __SAVE;
69	__RESTORE; __RESTORE; __RESTORE; __RESTORE;
70	__RESTORE; __RESTORE; __RESTORE; __RESTORE;
71
72	{
73		struct reg_window32 *rw = (struct reg_window32 *)regs->u_regs[UREG_FP];
74
75		/* Stop the back trace when we hit userland or we
76		 * find some badly aligned kernel stack. Set an upper
77		 * bound in case our stack is trashed and we loop.
78		 */
79		while(rw					&&
80		      count++ < 30				&&
81                      (((unsigned long) rw) >= PAGE_OFFSET)	&&
82		      !(((unsigned long) rw) & 0x7)) {
83			printk("Caller[%08lx]: %pS\n", rw->ins[7],
84			       (void *) rw->ins[7]);
85			rw = (struct reg_window32 *)rw->ins[6];
86		}
87	}
88	printk("Instruction DUMP:");
89	instruction_dump ((unsigned long *) regs->pc);
90	make_task_dead((regs->psr & PSR_PS) ? SIGKILL : SIGSEGV);
91}
92
93void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
94{
95	if(type < 0x80) {
96		/* Sun OS's puke from bad traps, Linux survives! */
97		printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
98		die_if_kernel("Whee... Hello Mr. Penguin", regs);
99	}
100
101	if(regs->psr & PSR_PS)
102		die_if_kernel("Kernel bad trap", regs);
103
104	force_sig_fault_trapno(SIGILL, ILL_ILLTRP,
105			       (void __user *)regs->pc, type - 0x80);
106}
107
108void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
109			    unsigned long psr)
110{
111	if(psr & PSR_PS)
112		die_if_kernel("Kernel illegal instruction", regs);
113#ifdef TRAP_DEBUG
114	printk("Ill instr. at pc=%08lx instruction is %08lx\n",
115	       regs->pc, *(unsigned long *)regs->pc);
116#endif
117
118	send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, current);
119}
120
121void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
122			 unsigned long psr)
123{
124	if(psr & PSR_PS)
125		die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
126	send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, current);
127}
128
129/* XXX User may want to be allowed to do this. XXX */
130
131void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
132			    unsigned long psr)
133{
134	if(regs->psr & PSR_PS) {
135		printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
136		       regs->u_regs[UREG_RETPC]);
137		die_if_kernel("BOGUS", regs);
138		/* die_if_kernel("Kernel MNA access", regs); */
139	}
140#if 0
141	show_regs (regs);
142	instruction_dump ((unsigned long *) regs->pc);
143	printk ("do_MNA!\n");
144#endif
145	send_sig_fault(SIGBUS, BUS_ADRALN,
146		       /* FIXME: Should dig out mna address */ (void *)0,
147		       current);
148}
149
150static unsigned long init_fsr = 0x0UL;
151static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
152                { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
153		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
154		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
155		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };
156
157void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
158		 unsigned long psr)
159{
160	/* Sanity check... */
161	if(psr & PSR_PS)
162		die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);
163
164	put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
165	regs->psr |= PSR_EF;
166#ifndef CONFIG_SMP
167	if(last_task_used_math == current)
168		return;
169	if(last_task_used_math) {
170		/* Other processes fpu state, save away */
171		struct task_struct *fptask = last_task_used_math;
172		fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
173		       &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
174	}
175	last_task_used_math = current;
176	if(used_math()) {
177		fpload(&current->thread.float_regs[0], &current->thread.fsr);
178	} else {
179		/* Set initial sane state. */
180		fpload(&init_fregs[0], &init_fsr);
181		set_used_math();
182	}
183#else
184	if(!used_math()) {
185		fpload(&init_fregs[0], &init_fsr);
186		set_used_math();
187	} else {
188		fpload(&current->thread.float_regs[0], &current->thread.fsr);
189	}
190	set_thread_flag(TIF_USEDFPU);
191#endif
192}
193
194static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
195static unsigned long fake_fsr;
196static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
197static unsigned long fake_depth;
198
199void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
200		 unsigned long psr)
201{
202	static int calls;
203	unsigned long fsr;
204	int ret = 0;
205	int code;
206#ifndef CONFIG_SMP
207	struct task_struct *fpt = last_task_used_math;
208#else
209	struct task_struct *fpt = current;
210#endif
211	put_psr(get_psr() | PSR_EF);
212	/* If nobody owns the fpu right now, just clear the
213	 * error into our fake static buffer and hope it don't
214	 * happen again.  Thank you crashme...
215	 */
216#ifndef CONFIG_SMP
217	if(!fpt) {
218#else
219	if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
220#endif
221		fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
222		regs->psr &= ~PSR_EF;
223		return;
224	}
225	fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
226	       &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
227#ifdef DEBUG_FPU
228	printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
229#endif
230
231	switch ((fpt->thread.fsr & 0x1c000)) {
232	/* switch on the contents of the ftt [floating point trap type] field */
233#ifdef DEBUG_FPU
234	case (1 << 14):
235		printk("IEEE_754_exception\n");
236		break;
237#endif
238	case (2 << 14):  /* unfinished_FPop (underflow & co) */
239	case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
240		ret = do_mathemu(regs, fpt);
241		break;
242#ifdef DEBUG_FPU
243	case (4 << 14):
244		printk("sequence_error (OS bug...)\n");
245		break;
246	case (5 << 14):
247		printk("hardware_error (uhoh!)\n");
248		break;
249	case (6 << 14):
250		printk("invalid_fp_register (user error)\n");
251		break;
252#endif /* DEBUG_FPU */
253	}
254	/* If we successfully emulated the FPop, we pretend the trap never happened :-> */
255	if (ret) {
256		fpload(&current->thread.float_regs[0], &current->thread.fsr);
257		return;
258	}
259	/* nope, better SIGFPE the offending process... */
260
261#ifdef CONFIG_SMP
262	clear_tsk_thread_flag(fpt, TIF_USEDFPU);
263#endif
264	if(psr & PSR_PS) {
265		/* The first fsr store/load we tried trapped,
266		 * the second one will not (we hope).
267		 */
268		printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
269		       regs->pc);
270		regs->pc = regs->npc;
271		regs->npc += 4;
272		calls++;
273		if(calls > 2)
274			die_if_kernel("Too many Penguin-FPU traps from kernel mode",
275				      regs);
276		return;
277	}
278
279	fsr = fpt->thread.fsr;
280	code = FPE_FLTUNK;
281	if ((fsr & 0x1c000) == (1 << 14)) {
282		if (fsr & 0x10)
283			code = FPE_FLTINV;
284		else if (fsr & 0x08)
285			code = FPE_FLTOVF;
286		else if (fsr & 0x04)
287			code = FPE_FLTUND;
288		else if (fsr & 0x02)
289			code = FPE_FLTDIV;
290		else if (fsr & 0x01)
291			code = FPE_FLTRES;
292	}
293	send_sig_fault(SIGFPE, code, (void __user *)pc, fpt);
294#ifndef CONFIG_SMP
295	last_task_used_math = NULL;
296#endif
297	regs->psr &= ~PSR_EF;
298	if(calls > 0)
299		calls=0;
300}
301
302void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
303			 unsigned long psr)
304{
305	if(psr & PSR_PS)
306		die_if_kernel("Penguin overflow trap from kernel mode", regs);
307	send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, current);
308}
309
310void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
311		       unsigned long psr)
312{
313#ifdef TRAP_DEBUG
314	printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
315	       pc, npc, psr);
316#endif
317	if(psr & PSR_PS)
318		panic("Tell me what a watchpoint trap is, and I'll then deal "
319		      "with such a beast...");
320}
321
322void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
323		       unsigned long psr)
324{
325#ifdef TRAP_DEBUG
326	printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
327	       pc, npc, psr);
328#endif
329	force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc);
330}
331
332void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
333			unsigned long psr)
334{
335	send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
336}
337
338void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
339			 unsigned long psr)
340{
341#ifdef TRAP_DEBUG
342	printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
343	       pc, npc, psr);
344#endif
345	send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
346}
347
348void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
349		       unsigned long psr)
350{
351	send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, current);
352}
353
354#ifdef CONFIG_DEBUG_BUGVERBOSE
355void do_BUG(const char *file, int line)
356{
357        // bust_spinlocks(1);   XXX Not in our original BUG()
358        printk("kernel BUG at %s:%d!\n", file, line);
359}
360EXPORT_SYMBOL(do_BUG);
361#endif
362
363/* Since we have our mappings set up, on multiprocessors we can spin them
364 * up here so that timer interrupts work during initialization.
365 */
366
367void trap_init(void)
368{
369	extern void thread_info_offsets_are_bolixed_pete(void);
370
371	/* Force linker to barf if mismatched */
372	if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
373	    TI_TASK        != offsetof(struct thread_info, task) ||
374	    TI_FLAGS       != offsetof(struct thread_info, flags) ||
375	    TI_CPU         != offsetof(struct thread_info, cpu) ||
376	    TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
377	    TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
378	    TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
379	    TI_KSP         != offsetof(struct thread_info, ksp) ||
380	    TI_KPC         != offsetof(struct thread_info, kpc) ||
381	    TI_KPSR        != offsetof(struct thread_info, kpsr) ||
382	    TI_KWIM        != offsetof(struct thread_info, kwim) ||
383	    TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
384	    TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
385	    TI_W_SAVED     != offsetof(struct thread_info, w_saved))
386		thread_info_offsets_are_bolixed_pete();
387
388	/* Attach to the address space of init_task. */
389	mmgrab(&init_mm);
390	current->active_mm = &init_mm;
391
392	/* NOTE: Other cpus have this done as they are started
393	 *       up on SMP.
394	 */
395}
396